Question

A certain steel railroad rail is 13 yd in length and weighs 75.9
lb/yd. How much thermal energy is required to increase the length
of such a rail by 3.0 mm? Note: Assume the steel has the same
specific heat as iron.

I tried this..using a specific heat of 450 and i got 4.23E6, its
saying im close, but not exact...Im not sure the specific heat to
use, please help

Your response is within 10% of the correct value. This may be due
to roundoff error, or you could have a mistake in your calculation.
Carry out all intermediate results to at least four-digit accuracy
to minimize roundoff error. J